Typhus, louse-borne epidemic is a disease of war and famine. Louse infestation is more common in cold climates where people live together in conditions of poor hygiene. Humans are the primary reservoir. Patients have a flu-like illness. Some patients have rash on the 5th or 6th day.
CASES/YEAR
50 (US); 1,000 (Global)
OTHER NAMES
Louse-borne typhus; Rickettsia prowazekii infection; Brill-Zinsser disease;
INCUBATION
1-2 weeks, usually 12 days; [CCDM]
INITIAL SYMPTOMS
Flu-like illness with fever, myalgia, and headache; Some patients have rash on the 5th or 6th day. [CCDM]
PRECAUTIONS
Standard; "Transmitted from person to person through close personal or clothing contact." [CDC 2007 Guideline for Isolation Precautions] "Isolation is not required after proper delousing of patient, clothing, living quarters, and household contacts." [CCDM, p. 663]
COMMENTS
EPIDEMIOLOGY:
Louse-borne typhus is a disease of war and famine. Louse infestation is more common in cold climates where people live together in conditions of poor hygiene. Humans are the primary reservoir, and flying squirrels (? Flea transmission) have been the source of sporadic cases. Some cases may occur after inhalation of infected louse feces. [CCDM, p. 662] Transmission occurs when infected louse feces are scratched into the skin or rubbed into the conjunctiva. [PPID, p. 2369] Outbreaks often occur during the colder months among impoverished and refugee populations. [CDC Travel, p. 329] "In severe cases, shock occurs and the fatality rate of epidemic typhus is 20 to 30% when untreated." [Cecil, p. 2022]
FINDINGS
About 5-6 days after onset of the fever, a maculopapular rash starts on the trunk and spreads to the extremities (not on the palms/soles). Some patients have cough and tachypnea. Neurological complications include confusion, coma, seizures, and hearing loss. Brill-Zinsser disease is recurrence of a milder form of the disease as long as years after the initial infection. [CCDM, p. 661] In addition to flu-like symptoms and rash, common findings are delirium, vomiting, abdominal pain, normal WBC count, thrombocytopenia, elevated transaminases, and blood and protein in the urine. Complications include renal injury and pneumonia. [ID, p. 1486] The small pink macules first appear in the axilla and upper trunk on days 4-6. A petechial rash may develop in severe cases. [Merck Manual, p. 1694] In a case series in Ethiopia, patients also had conjunctivitis (53%) and jaundice (17%). [Guerrant, p. 330-1] Rash occurs in about 50% of patients. [PPID, Table 185.3] Conjunctivitis and constipation are prominent in many cases. Myalgia was marked in recent series of cases in Ethiopia and Burundi. [PPID, p. 2370] Epistaxis is a common symptom. Meningoencephalitis with stiff neck is common in severe cases. [Cohen, p. 1096]
DIAGNOSTIC
Paired serum antibodies; PCR; [ID, p. 1486] Diagnostic titers (1:128 for IgG and 1:32 for IgM) or a four-fold rise are usually detectable by the second week of illness. [PPID, p. 2370-1]
SCOPE
Central Africa, Asia, North/Central/South America; [CDC Travel] Endemic areas in mountainous Mexico, Central and South America, central and east Africa, and many countries in Asia; [CCDM]
SIGNS & SYMPTOMS
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>arthralgia
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>fever
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>myalgia
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E epistaxis
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G abdominal pain
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G constipation
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G diarrhea
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G jaundice
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G liver function test, abnormal
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G nausea, vomiting
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H anemia
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H leukocytosis
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H leukopenia
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H splenomegaly
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H thrombocytopenia
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N confusion, delirium
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N headache
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N lethargy
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N seizure
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N stiff neck
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O conjunctivitis, acute
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R cough
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S papules or plaques
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S petechiae and ecchymoses
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S rash (exanthem)
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U hematuria
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X lung infiltrates
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*acute renal failure
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*encephalitis
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*meningitis
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*myocarditis
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*pneumonia
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*shock
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*stupor, coma
ENTRY
Inhalation, Skin or Mucous Membranes (Includes Conjunctiva)
RISK FACTORS
- Travel to endemic area
- Victim--air release of infectious agents
TREATMENT
Vaccination is effective, but not generally available. [Merck Manual, p. 1694]
REFERENCES FOR CASES/YEAR
1. (US) Almost completely eliminated from US; [Gorbach, p. 400] The last outbreak was in 1922. A few cases were reported in 1970s and 1980s associated with the eastern flying squirrel and its ectoparasites. [ID, p. 1485] Guesstimate: 1/20 of global cases/yr;
2. (Global) 100,000 people were infected in an outbreak in the 1997 civil war in Burundi; Cases were reported in the 1990s in Russia, Peru, Algeria, France, and the US; [Cecil, p. 2022] Guesstimate: 1000/year;